1. Field of the Invention
This invention relates to an image correcting device for a motor vehicle (referred to as in-vehicle image collecting device) and a night driving view field supporting device. More particularly, this invention relates to an in-vehicle image correcting device for correcting an image ahead of one's own vehicle in which an obstacle is difficult for a driver to visually recognize and is picked up by a near-infrared camera so that it can be visually recognized by the driver. This invention also relates to a night driving view field supporting device for supporting the driving field of the driver at night in such a way that the image picked up by the near-infrared camera is displayed on a head-up display device.
2. Description of the Related Art
In recent years, in order to improve the visibility of a driver, a projecting type display unit called a head-up display device (HUD) which displays a virtual image reflected from a front glass has been adopted in some models of motor vehicles.
It is generally accepted that a human being receives the main information from this world by visual sense so that during driving the importance of the visual sense has increased greatly. As the driver senses the obstacle earlier in a moving direction, he can deal with the obstacle with adequate time. Therefore, a night driving view field supporting device (night vision) for supporting safe driving has been proposed for the purpose of assuring the view field at night or under adverse conditions.
This device includes an infrared camera attached to the front of a vehicle, a computer and the above HUD. The image representative of infrared rays (heat) emitted by objects collected by the infrared camera appears as a monochromatic image on the HUD. Therefore, the driver recognizes invisible obstacles in the dark, and those ahead of one's own vehicle when the view field is not clear because of rain and fog.
However, the infrared camera used in the night driving view field supporting device detects heat of an object to be picked up and displays it as a display brightness difference (a hot object appears bright). An obstacle such as a living thing, which generates heat poses no problem. However, an obstacle which does not generate heat or gives a small temperature difference from an ambient temperature may not appear bright. A walker who wears cold-proof clothing does not appear bright.
In order to obviate such an inconvenience, a near-infrared camera has been proposed as a camera. However, if the monochromatic image captured by the near-infrared camera is displayed as it is on the HUD, in addition to the obstacle, a street lamp and headlight of an oncoming cars all of which generate a large quantity of lights appear to overflow. Such an appearance makes it difficult for the driver to recognize the obstacle. Thus, the night driving view field supporting device cannot achieve the essential object.